Rheostat.



PATENTED MAR. 15,1904.

L. LYNDON.

RHEOSTAT. APPLICATION FILED AUG. 8. 1902.

H0 MODEL.

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UNITED STATES Patented March 15, 1904.

PATENT OFFICE.

LAMAR LYNDON, OF NEW YORK, N. Y., ASSIGNOR TO NATIONAL BAT- TERYCOMPANY, OF BUFFALO,

NEW JERSEY.

NEW YORK, A CORPORATION OF RHEOSTAT.

SPECIFICATION forming part of Letters Patent No. 754,660, dated March15, 1904.

Application filed August 8, 1902.

To all whom it may concern:

Be it known that I, LAMAR LYNDON, a citizen of the United States,residing in the borough of Manhattan, city of New York, State of New'York, have invented certain new and useful Improvements in Rheostats,of which the following is a specification, reference being had to theaccompanying drawings, forming a part hereof.

This invention relates to devices for varying the potential of a currentof electricity, and more especially to devices of this nature whereinthe current is adapted to be passed through one or more of severalresistances in order to effect the variations.

While the invention is not limited in its application to any specificuse or purpose, it is particularly applicable for producing such changesof potential as are desirable in currents flowing throughfield-windings, translating devices, and coils in general, and thesecoils and all other such devices for receiving a current of electricitywill be referred to hereinafter as receiving devices.

The present invention is particularly concerned with the mode ofconnecting up the aforesaid resistances, both with respect to the lineand the receiving device and also with respect to each other.

Among the different forms of rheostats' in use heretofore and designedto effect variations in potential for the purposes above indicated theremay be found, in general, two methods of connecting up resistances withrespect to the line and receiving device. One of these methods is toplace the receiving device and the resistances in series on the line,any or all of the resistances being adapted to be cut out from the line,and the other method is to bridge the resistances across the line and toconnect up the receiving device, so that it may be placed at will inseries with a part or none of the resistances and parallel with theremaining part or all of the resistances, respectively. The objection tothe first method of connecting up the resistances with respect to theline and receiving device is that with this arrangement it is neverpossible to obtain Serial No. 118,864. (No model.)

a potential of zero across the terminals of the receiving device, whilethe second arrangement is uneconomical, inasmuch as the total currentcan never flow through the receiving device, the energy of a part of thecurrent being thereby wasted.

The object of the present invention, accordingly, is to provide arheostat which by being properly connected with the receiving device andthe line will permit the total current to flow through said receivingdevice whenever it is desired and with which it will be possible to varyat will the potential of the current in said receiving device from Zeroto the maximum.

In the drawings, where the device is shown diagrammatically, Figure 1represents the improved form of rheostat described herein. Figs. 2 and 3represent modifications in the improved rheostat more particularlydescribed hereinafter.

Referring now to the improved forms of rheostats shown diagrammaticallyin Figs. 1 to 3, inclusive, A and B indicate the supplymains; O,areceiving device; D, the controllerarm of the rheostat, and a and b theresistances and contacts, respectively, of the rheostat. In Fig. l theterminals of the resistances are connected with the adjacentcontactbuttons, respectively, and the extreme contact F is connectedwith the line. The other extreme contact E is connected with oneterminal of a switch, (indicated at Gr,) the other terminal of saidswitch being connected with the line by the conductor 0. Carried bycontroller-arm D and insulated therefrom is a contact-plate (Z, theswitch G and arm D being so placed with reference to each other upon therheostat-box that in one portion of the travel of arm D contact (Z willconnect the two terminals of the switch G, while at a predeterminedpoint in the travel of said arm the contact (Z will be moved off theterminals of the switch and the circuit through said switch will bebroken. So far as this invention is concerned the precise point at whichsaid circuit is broken is immaterial, it being shown in the drawings,Fig. 1, to be just after arm Fig. 3, is proposed.

D passes the fifth contact-button in its movement toward the right.

It is evident from Fig. 1 that when the arrangement just described isput in operation the current which flows in conductor A will divide at0, part flowing in conductor 0 through the resistances to conductor Band part through receiving device C and arm D, thence through certain ofthe resistances, (depending upon the position of arm D,) and finally toconductor B, the relative portions of the current flowing over each pathdepending upon the electrical resistance of each path. If, however, theposition of arm D be moved from the position shown in Fig. 1 to theposition indicated by dotted lines in the same figure, the current willcease to flow over the first of the above-mentioned paths and the totalcurrent will flow through the receiving device C. It will be seen thatthe current through the receiving device C may be entirely cut out, andaccordingly the difference of potential between the terminals of thereceiving device will be zero, and that by moving the arm to the rightthe potential between said terminals may be increased through varyingvalues to a maximum, which will occur when the arm is in contact withthe other extreme contact-button F. As the controller-arm D of therheostat is moved to the right from button to button the variations ofpotential in the receiving device C, providing the re sistances are allequal each to each, will be equicrescent except at the point where theswitch is opened. At this point as the controller-arm is moved to theright the voltage at the terminals of the receiving device will beincreased by an amount much larger than that due to cutting out thesingle resistance between buttons 5 and 6, Fig. 1, owing to the cuttingout of the circuitbridged across the line. In order to prevent thisrelatively large variation, one of the resistances may be omitted, as isshown in Fig. 2, the resistancecoil between buttons 3 and 4; being leftout,

there being, however, a conductor connecting these two buttons. Inpassing from button 3 to button 1 of the rheostat the arm D is adaptedto cut out all the resistances in parallel, but none of the resistancesin series with the receiving device.

For some purposes it may be desirable to prevent an excessive rise ofvoltage at the terminals of the receiving device which would be due tothe opening of switch G with a current of high voltage. Accordingly thearrangement for connecting up the resistances with respect to eachother, as illustrated in In Fig. 5 there are no resistances orconductors connecting buttons v3 and 4:, 4. and 5, or 5 and 6; but threeconductors are provided to connect, respectively, buttons 1 and 4, 2 and5, and 3 and 6. With this arrangement it will be obvious that thecurrent will travel as follows: When arm D is in contact with theextreme button E, resistances Nos. 1 to 11 are in series across theline, and as button E is connected with the line at w the potential inthe receiving device will be equal to Zero. When the controllerarm is onthe button No. 2, the voltage through the receiving device will be dueto the drop in the resistance-coil between buttons 1 and 2. When thecontroller-arm is on button No. 3, the voltage through the receivingdevice is increased by the amount of the drop between buttons 1 and 3. When the controller passes to button No 4;, the circuit across the lineis cut out on account of the opening of the switch, and to prevent anextreme rise of voltage in the receiving device the resistances betweenbuttons 1 and 3 are again thrown in, and (buttons 1 and 4: beingconnected by a suitable conductor) the path of the current is from arm Dto button 4, to button 1, to button 11. hen the controller passes tobutton No. 5, the resistance between buttons 1 and 2 is again cut out,and when the controller passes to button No. 6 the resistance betweenbuttons 2 and 3 is cut out. Finally, as the controller D passes frombutton 6 to 11 the path of the current is simply that of an ordinaryrheostat, the only resistances in circuit being between the end of thecontroller-arm and extreme contact-button F, which resistances are inseries with the receiving device.

It will be evident that instead of employing an arm, as D, to operatethe switch and control the circuit through the rheostat any othersuitable means may be employed which will effect both of theseoperations, and thereby produce the variations of current potential inthe manner heretofore described, and this invention is accordingly notrestricted to the use of a controller-arm as the only means ofperforming these functions.

I claim as my invention- 1. In combination for the purposes hereinbeforeset forth, a plurality of resistances electrically connected and bridgedin circuit across the line, a receiving device with which saidresistances are adapted to be connected either in parallel or partly inseries and partly in parallel, means for so connecting said resistancesand receiving device, and a switch operated by said means to open thecircuit across the line at a predetermined point, substantially asdescribed.

2. In combination for the purposes hereinbefore set forthaplurality ofresistances electrically connected and bridged in circuit across theline, a receiving device with which said resistances are adapted to beconnected either in parallel or partly in series and partly in parallel,a controller-arm in circuit with said receiving device for so connectingsaid resistances and receiving device, and a switch operated by said armto open the circuit across the line at a predetermined point,substantially as described.

ed to operate said switch and thereby to open the circuit across saidline at a predetermined point, substantially as described.

4. In a rheostat, the combination of a plurality of resistances adaptedto be bridged in series across the line, a plurality of contacts towhich said resistances are connected, a controller-arm in circuit uponthe line and adapted to make electrical connection with any of saidcontacts whereby to include certain of said resistances in series uponthe line, and a switch controlling said circuit across the line andoperated by said arm to open said circuit across the line at apredetermined point, substantially as described.

5. The combination with a rheostat having a plurality of resistancesadapted to be placed in circuit across the supply-mains, a plurality ofcontacts to which said resistances are connected, a switch controllingsaid circuit across the supply-mains, and a controller-arm adapted tomake electrical connection with any of said contacts and also adapted tooperate said switch, of a receiving device in circuit on the linebetween said arm and one terminal of said circuit across thesupply-mains, said arm at one extreme contact placing all theresistances in series across the supply-mains and at a predeterminedpoint as it moves toward the other extreme contact opening the circuitacross the supply-mains, the only resistances receiving current aftersaid arm passes said predetermined point being the resistances includedbetween the end of the arm and said other extreme contact, substantiallyas described.

6. In a rheostat, the combination of a plurality of resistances inelectrical connection, contacts at both ends of said plurality ofresistances whereby currentmay be supplied to the same, a switch inseries with said resistances comprising a pair of terminals and acontact piece, one of said terminals being connected with one main ofthe supply-circuit and the other of said terminals being connected withone of said contacts, the second of said contacts being connected to theother supply-main, a controller-arm adapted to be placed in circuit onthe line and carrying said contact-piece, said arm being also adapted tomake electrical contact with any of the resistances and thereby to beplaced in series with a part of said resistances and in parallel withthe rest of said resistances until said arm is moved to open said switchwhen the current will only flow through certain of the resistances allof which will be serially connected with said arm and in circuit on theline, substantially as described.

7. In a rheostat, the combination of a plurality of contacts arrangedserz'atz'm, a plurality of resistances severally placed between certainbut not all of the pairs of adjacent contacts and having their terminalselectric- .ally connected with said adjacent contacts respectively, saidcontacts and resistances being adapted to be bridged in circuit acrossthe line, a switch controlling said circuit across the line, acontroller-arm in circuit on the line and adapted to make electricalconnections with any of the contacts, said arm being also adapted tooperate said switch and thereby to open the circuit across the line at apredetermined point, and a plurality of conductors electricallyconnecting certain pairs of said contacts which are not adjacent,substantially as and for the purpose set forth.

8. In a rheostat, the combination of a plurality of contacts arrangedsem'rttz'm, a resistance inserted between each of the adjacent contactsexcept between the contacts 3 and 4, 4 and 5 and 5 and 6, respectively,the terminals of said resistances being electrically connected withtheir adjacent contacts respectively, and three conductors connectedrespectively with contacts 1 and 4:, 2 and 5, and 3 and 6, substantiallyas and for the purpose set forth.

9. The combination of a supply-circuit, a regulated circuit, aresistance having a plurality of contact-points, a regulator-arm adaptedto cooperate with said contact-points to determine the amount ofresistance in series with the regulated circuit, and means operated bysaid regulator-arm to place some of the resistance in parallel with theregulated circuit, whereby by adjusting the position of said arm littleor no current may be made to flow through the regulated circuit, thevoltage of which will be that which results from the fall of potentialalong the parallel resistance, and whereby a greater amount of currentmay be made to flow through the regulated circuit by cutting out theparallel resistance and as much of the series resistance as is desired.

This specification signed and witnessed this 15th day of July, A. D.1902.

LAMAR LYNDON.

In presence of- ALFD. W. BIDDLE, A. N. J ESBERA.

